Field of the Invention
The present invention relates to a substrate treatment apparatus that controls respective units by a master-slave method.
Description of the Background Art
As a substrate treatment apparatus, there is known a single wafer apparatus that treats substrates such as semiconductor wafers one by one. This type of apparatus includes: a plurality of treatment units; a conveying robot capable of conveying the substrates to the respective treatment units; and a control unit, then controls the plurality of treatment units and the conveying robot by the control unit, and thereby executes substrate treatment sequentially for a plurality of the substrates.
In this case, in general, the control unit is defined as a master device, drivers of the respective treatment units and the conveying robot are defined as a plurality of slave devices placed in a relatively lower control hierarchy than that of the master device, and the master device controls the plurality of slave devices by a master-slave method.
For example, in Japanese Patent Application Laid-Open No. 2010-123709, into treatment liquid supply pipes which supply treatment liquids to the substrates in the respective treatment units, there are interposed: valve control units (slave devices), which adjust flow rates of the treatment liquids flowing through the pipes by valves; and flowmeters (slave devices), which measure the flow rates of the treatment liquids flowing through the pipes. Then, values of the flow rates measured by the flowmeters are given to the valve control units via a control unit (master device), and feedback control, which adjusts valve openings by the valve control units based on such flow rate values, is performed.
However, in the above-described mode of performing data transfer via the control unit (master device), as the slave devices controlled by the master device have been being increased, a load applied to the master device has been increased, and it has been difficult to ensure real time properties of the above-described feedback control.
In this connection, as another mode, a mode is also conceivable, in which the flowmeters and the valve control units are connected to each other by analog signal lines, and the data transfer of the flow rate values is directly performed from the flowmeters to the valve control units. However, in this mode, though it has been made possible to ensure the real time properties of the above-described feedback control while reducing the load applied to the master device, there have occurred an error owing to digital/analog conversion and a delay of a speed of signal transmission. Moreover, a necessity to provide an additional instrument for transferring analog signals has arisen, and has brought about a size increase and cost increase of the apparatus.
These problems are not only applied to the substrate treatment apparatus that performs the above-described flow rate adjustment, and are problems common to a variety of substrate treatment apparatuses, each of which includes: a measuring slave that measures, as an index value, at least one physical quantity regarding an operation state of substrate treatment; and an adjustment unit that adjusts the above-described operation state based on a measurement result by the measuring slave.